1. Field of the Invention
This invention relates to a power-driven conveyor for lifting liquid from a source, moving the liquid laterally from the source to a position above a nearby holding tank, and stripping liquid from the conveyor to fall by gravity into the holding tank. More specifically, it concerns an endless cable that is trained about a plurality of pulleys with flight receiving pockets therein and a plurality of flights that are located at spaced intervals along the cable for transmitting motion between the cable and the pulleys.
2. Description of the Prior Art
Steel balls with axial bores have been threaded like beads upon a cable and swaged thereon at spaced intervals. The ends of the cable have been joined together to form a loop, and the loop has been used as a drive belt for transmitting motion between a plurality of pulleys having pockets therein for receiving portions of the steel balls. Such balls tend to stiffen the cable because the entire length of the cable passing diametrically through each ball is supported by the ball. Furthermore, threading balls on a cable can be difficult when the cable is of great length and many balls are required.
Endless belt strands or chain-like members have been used to lift viscous liquid from wells, such as heavy crude oil from oil wells. Endless carriers are shown in U.S. Pat. No. 930,465, issued Aug. 10, 1909, to Fowler; U.S. Pat. No. 1,703,963, issued Mar. 5, 1929, to Scruby; U.S. Pat. No. 3,774,685, issued Nov. 27, 1973, to Rhodes; and U.S. Pat. No. 4,089,784, issued May 16, 1978, to Ettelt, et al.
An endless cable with washers thereon is shown in U.S. Pat. No. 1,769,336, issued Jul. 1, 1930, to Detaint, et al. An endless cable with rubber lifters inserted between the cable strands at intervals spaced along the cable is disclosed in Heavy Oiler, Issue 13, Apr. 1985, pages 14-15. Heavy Oiler is a quarterly newsletter published by UNITAR/UNDP INFORMATION CENTER FOR HEAVY CRUDE AND TAR SANDS, 336 East 45th Street, New York, N.Y. 10017. An endless cable with compressible cups thereon is shown in U.S. Pat. No. 3,289,593, issued Dec. 6, 1966, to Corry. An endless coil spring wrapped about spaced heads interconnected by chains is disclosed by U.S. Pat. No. 587,124, issued Jul. 27, 1897, to James. Endless chains with buckets attached are shown in U.S. Pat. No. 1,481,735, issued Jan. 22, 1924, to Peck; U.S. Pat. No. 1,558,490, issued Oct. 27, 1925, to Mayberry; and U.S. Pat. No. 4,552,220, issued Nov. 12, 1985, to Jones. The buckets in U.S. Pat. No. 1,558,490 have a ball-like shape with openings therein and liquid is carried inside the buckets.
When endless belt strands or cable are used for lifting liquid from a source, it is desirable to increase the diameter of width of a column of liquid surrounding the upwardly noving cable and thereby the liquid output of the lift. When a cable is coated with viscous liquid, such as a heavy oil, there is a tendency for it to slip on a drive pulley, and sometimes more positive means than merely being trained thereabout are required for transmitting motion between the pulley and the cable. Preferrably, oil should be stripped from the cable before reaching the drive pulley. The cable should be flexible so that it can be trained about a small diameter pulley, and both ascending and descending cable portions can be located within a narrow passage, such as a well casing.